<!DOCTYPE html>
<html>
  <head>
    <title>Force-Directed Layout</title>
    <script type="text/javascript" src="http://d3js.org/d3.v2.min.js?2.9.3""></script>
    <style>

    .link {
      stroke: #ccc;
    }

    .node text {
      pointer-events: none;
      font: 10px sans-serif;
    }

    </style>
  </head>
  <body>
    <div id="chart"></div>
<script>

var width = 960,
    height = 500,
    fill = d3.scale.category20();

var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

var force = d3.layout.force()
    .gravity(.05)
    .distance(100)
    .charge(-100)
    .size([width, height]);

d3.json("force.json", function(json) {
  force
      .nodes(json.nodes)
      .links(json.links)
      .start();

  var link = svg.selectAll(".link")
      .data(json.links)
    .enter().append("line")
      .attr("class", "link");

  var color = d3.scale.category20();

  var node = svg.selectAll(".node")
      .data(json.nodes)
    .enter().append("g")
      .attr("class", "node")
      .call(force.drag);

  node.append("circle")
      .attr("r", 8)
      .style("fill", function(d) { return color(d.id == "me" ? 1 : 2); });

  node.append("text")
      .attr("dx", 12)
      .attr("dy", ".35em")
      .text(function(d) { return d.id });

  force.on("tick", function() {
    link.attr("x1", function(d) { return d.source.x; })
        .attr("y1", function(d) { return d.source.y; })
        .attr("x2", function(d) { return d.target.x; })
        .attr("y2", function(d) { return d.target.y; });

    node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
  });
});

</script>

  </body>
</html>
